| Defensin is a class of endogenous cationic antimicrobial peptides widely existing in plants and animals. Its structure contains rich arginine, disulfide bond and conserved cysteine residues. According to the location and connection of cysteine, Human defensins are divided into two major categories:α-defensins andβ-defensins(HBD). Studies found that humanα-defensins are mainly distributed in the intestine and vagina;β-defensins are distributed in the skin, respiratory epithelium and oral mucosa and other parts. As the first line of defense, they are participating in the body's immune defenses system. Currently known thatβ-defensins has a variety of subtypes, the most famous are HBD-l～HBD-4. Recent studies have found that HBD were existing in odontoblast cells. It suggested that excepting the ability of composing dentinal matrix, odontoblast cells were involved in the pulp immune system. There is few report about HBD expressing and distributing in human dental pulp nor its role in the pulp repair process and pulp development. There is still no report about this in our country. In this study, immunohistochemical technique was applied to detect the expression and distribution of HBD in human pulp. Then study its role in the physiological and pathological pulp tissue.Objectives1. To investigate the expression of human beta defensins (HBD-1/HBD-4) in dental pulp tissue and to study the role of HBD-1/HBD-4 on dental pulp restoration after injury.2. To observe the expression and distribution of HBD-1/HBD-4 in the human dental pulp of permanent teeth during the root formation. Study the relationship between HBD-1/HBD-4 and the development of human dental pulp in permanent teeth.Material and Methods1. Immunohistochemical technique was applied to detect the expression and distribution of HBD-1/HBD-4 in human normal (15 cases), carious (15 cases) and inflammatory (15 cases) pulp tissue. PBS was used as a control by taking place of HBD-1/HBD-4 antibody. IMAGE PRO-PLUS 5.1 sofeware was used to test the optical density of odontoblasts staining. Differences among the three groups were analyzed by one-way ANOVA or wilcoxon test with SPSS 13.0 software.2. Based on the teeth root eight development status, the pulp tissue were classified into two groups:apical unclosed and apical closed. The pulp were immunotistochemically examined by using of HBD-1/HBD-4 antibody. SPSS 13.0 software was used to test the statistical data.Results1. The expression of HBD-1/HBD-4 was positive in the odontoblast cells.2. HBD-1 showed moderate expression in normal, deep caries and inflammatory groups, and no significant difference among the three groups.3. The expression of HBD-4 in the normal group was weaker than the other two groups (P<0.01). In the inflammatory group, it showed strong positive expression the in deep caries group (P<0.01).4. The expression of HBD-1 was positive in apical unclosed permanent teeth, and no significant difference with apical closed group. In apical unclosed group, the expression of HBD-1 was positive in the crown and neck odontoblast cells, but negative in the root odontoblast cell.5. In apical unclosed group, the expression of HBD-4 were weak positive in the crown and neck odontoblast cells but stronger positive in the root odontoblast cell than crown and neck.Conclusions1. HBD-1 is constitutively expression in the dental pulp. It may be involved in the construction of pulp natural immune system.2. HBD-4 is related to the course and development of pulpitis. The different expression of HBD-4 between three groups shows that HBD-4may play an important role during the restoration of odontoblasts after dental injury.3. With the development of root formation, the expression of HBD-1/HBD-4 in dental pulp shows different characteristics. HBD-1/HBD-4 may play a role in formation of pulp immune system during the dental pulp development. |
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